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Tutorials and Examples

LMGP suite for Windows by Jean Laugier and Bernard Bochu

Basic Demonstration of Poudrix Powder X-ray and Neutron Pattern Calculation Software

The CCP14 Homepage is at http://www.ccp14.ac.uk
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Powdrix: Powder Pattern Calculation of Synchrotron/Laboratory X-ray and Neutron Powder Diffraction Patterns including the ability to use either "Brenann and Cowan or Sasaki" Anomalous Dispersion data to calculate the contribution of f' and f'' - plus plot in 2-theta and Q-space.

Latest Poudrix Updates and Hints

Poudrix is obtained as a Windows executable from the LMGP (Laboratoire des Materiaux et du G�nie Physique de l'Ecole Sup�rieure de Physique de Grenoble http://www.inpg.fr/LMGP/) suite program area at http://www.ccp14.ac.uk/ccp/web-mirrors/lmgp-laugier-bochu/.

Run Poudrix by executing it from an ICON or file the Windows Explorer to give the following starting screen

    		•

    You can either enter the structure by hand or open various structure file formats including Poudrix, Shelx, PowderCell and Lazy Pulvarix formats. In this case, we will open the calcite structure up which is in PowderCell format.

    		•
    A very nifty feature in Poudrix is not only the ability to have single wavelength data but also multiwavelength including default or user specified impurity peaks. Under Experiment, choose Multiple W.L. whereon you are presented with a number of default options. Choosing Cu brings up the following screen.

    		•
    The third wavelength at 1.39222 refers to Cu k beta. This is more likely to be around 0.2% on some XRD systems so set it to this.

    Now we can read in the Anomalous Dispersion factors. Poudrix prompts whether we wish to use the Brenann and Cowan or Sasaki f' and f''.

  • In this case, we will read in the Sasaki based f' and f'' anomalous dispersion factors.

    • It is also possible to input the Polarisation of the X-ray beam for either sealed X-ray tube or Synchrotron. Just click on the top right XRAY icon to bring up this option.

  • In this case, we will use the Sealed X-ray tube. Now selecting the top right hand Calcul ICON will now calculate the powder diffraction pattern on the bottom screen.

    • It is also possible to open up a real or calculated powder pattern and overlap it with the newly generated powder patter. From the bottom Powder Plot Window, use the File, Open option.

    		•
    It is also possible to get a detailed output from the Results menu.

    POUDRIX. Powder diffraction diagram (Source: X ray tube)
--------------------------------------------------------

08/11/99 00:07:44

Cell   :    4.989   4.989  17.062  90.000  90.000 120.000
Lambda :    1.39222
S.Group: R-3C
Syst.  : HEXA
Bravais: R
Centro

Space group positions:
X,Y,Z                    
-Y,X-Y,Z                 
Y-X,-X,Z                 
-Y,-X,Z+1/2              
Y-X,Y,Z+1/2              
X,X-Y,Z+1/2              

Bravais lattice translations:
  0.333333  0.666667  0.666667
  0.666667  0.333333  0.333333

Conditions limiting the existence (lattice):
-h+k+l=3n

3 conditions limiting the existence (general position):
h=-k,  l=2n
h=0,  l=2n
k=0,  l=2n

Asymetric unit content:
           x        y        z      B      Pop.   Mult. Elem. Nb.
CA    0.00000  0.00000  0.00000  0.50   1.000   0.333    1
 C    0.00000  0.00000  0.25000  0.40   1.000   0.333    2
 O    0.25930  0.00000  0.25000  0.00   1.000   1.000    3

Atomic scattering factors 
      f(0)        f'        f"        f'        f"        f'        f"
CA   20.0000    0.3570    1.0750    0.3400    1.2850    0.3390    1.2910
C    5.9992    0.0140    0.0070    0.0170    0.0090    0.0170    0.0090
O    7.9994    0.0390    0.0260    0.0460    0.0320    0.0470    0.0320

Cromer Factors
       c       a1     b1       a2      b2      a3      b3      a4      b4
CA  1.3751  8.6266 10.4421  7.3873  0.6599  1.5899 85.7484  1.0211178.4370
C  0.2156  2.3100 20.8439  1.0200 10.2075  1.5886  0.5687  0.8650 51.6512
O  0.2508  3.0485 13.2771  2.2868  5.7011  1.5463  0.3239  0.8670 32.9089
The intensities were plied by: 6.4733E-0004

Results for lambda= 1.39222

 Nb    h  k  l   2Theta   dhkl    N    LP       Intensity 
  1    0  1  2   20.809  3.8544   6  29.21       146.43
  2    1  0  4   26.515  3.0354   6  17.59      1542.27
  3    0  0  6   28.339  2.8437   2  15.27        35.52
  4    1  1  0   32.408  2.4945   6  11.45       216.86
  5    1  1  3   35.483  2.2844  12   9.40       335.52
  6    2  0  2   38.829  2.0942   6   7.71       249.31
  7    0  2  4   42.348  1.9272   6   6.35       104.45
  8    0  1  8   42.691  1.9124   6   6.24       332.20
  9    1  1  6   43.581  1.8752  12   5.96       368.02

Structure factors
 Nb    h  k  l     A+      B+      A-      B-       F+       F-      Fmoy
  1    0  1  2   35.39    6.22   35.39    6.22    35.93    35.93    35.93
  2    1  0  4  150.11    6.54  150.11    6.54   150.25   150.25   150.25
  3    0  0  6  -41.98    5.84  -41.98    5.84    42.39    42.39    42.39
  4    1  1  0   69.55    6.19   69.55    6.19    69.83    69.83    69.83
  5    1  1  3   67.78    0.33   67.78    0.33    67.78    67.78    67.78
  6    2  0  2   91.02    6.38   91.02    6.38    91.24    91.24    91.24
  7    0  2  4   64.76    6.12   64.76    6.12    65.05    65.05    65.05
  8    0  1  8  116.89    6.41  116.89    6.41   117.07   117.07   117.07
  9    1  1  6   88.94    6.36   88.94    6.36    89.17    89.17    89.17

Results for lambda= 1.54056

 Nb    h  k  l   2Theta   dhkl    N    LP       Intensity 
  1    0  1  2   23.055  3.8544   6  23.60       118.80
  2    1  0  4   29.400  3.0354   6  14.12      1238.39
  3    0  0  6   31.433  2.8437   2  12.23        29.01
  4    1  1  0   35.973  2.4945   6   9.12       172.73
  5    1  1  3   39.411  2.2844  12   7.46       266.90
  6    2  0  2   43.162  2.0942   6   6.09       196.98
  7    0  2  4   47.117  1.9272   6   5.00        82.12
  8    0  1  8   47.503  1.9124   6   4.90       261.19
  9    1  1  6   48.506  1.8752  12   4.68       289.06

Structure factors
 Nb    h  k  l     A+      B+      A-      B-       F+       F-      Fmoy
  1    0  1  2   35.23    7.42   35.23    7.42    36.00    36.00    36.00
  2    1  0  4  150.07    7.83  150.07    7.83   150.27   150.27   150.27
  3    0  0  6  -42.23    6.96  -42.23    6.96    42.80    42.80    42.80
  4    1  1  0   69.42    7.40   69.42    7.40    69.81    69.81    69.81
  5    1  1  3   67.87    0.41   67.87    0.41    67.87    67.87    67.87
  6    2  0  2   90.95    7.63   90.95    7.63    91.26    91.26    91.26
  7    0  2  4   64.64    7.32   64.64    7.32    65.05    65.05    65.05
  8    0  1  8  116.85    7.67  116.85    7.67   117.10   117.10   117.10
  9    1  1  6   88.87    7.60   88.87    7.60    89.20    89.20    89.20

Results for lambda= 1.54439

 Nb    h  k  l   2Theta   dhkl    N    LP       Intensity 
  1    0  1  2   23.114  3.8544   6  23.47       118.15
  2    1  0  4   29.475  3.0354   6  14.04      1231.71
  3    0  0  6   31.513  2.8437   2  12.17        28.89
  4    1  1  0   36.065  2.4945   6   9.07       171.71
  5    1  1  3   39.513  2.2844  12   7.42       265.47
  6    2  0  2   43.275  2.0942   6   6.05       195.85
  7    0  2  4   47.241  1.9272   6   4.97        81.61
  8    0  1  8   47.629  1.9124   6   4.87       259.64
  9    1  1  6   48.634  1.8752  12   4.65       287.35

Structure factors
 Nb    h  k  l     A+      B+      A-      B-       F+       F-      Fmoy
  1    0  1  2   35.22    7.46   35.22    7.46    36.00    36.00    36.00
  2    1  0  4  150.06    7.86  150.06    7.86   150.27   150.27   150.27
  3    0  0  6  -42.25    7.00  -42.25    7.00    42.83    42.83    42.83
  4    1  1  0   69.41    7.43   69.41    7.43    69.81    69.81    69.81
  5    1  1  3   67.88    0.41   67.88    0.41    67.88    67.88    67.88
  6    2  0  2   90.95    7.66   90.95    7.66    91.27    91.27    91.27
  7    0  2  4   64.63    7.35   64.63    7.35    65.05    65.05    65.05
  8    0  1  8  116.85    7.71  116.85    7.71   117.10   117.10   117.10
  9    1  1  6   88.87    7.64   88.87    7.64    89.20    89.20    89.20

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